Biopsy Study to Improve Detection of Cervical Precancer

A collaborative study on colposcopic biopsy is being conducted at the University of Oklahoma, as part of an established project on cervical cancer risk-marker discovery. The aims of the study are to study cervical disease on the lesion level, to optimize criteria for biopsy placement, and to analyze the incremental benefit of taking multiple biopsies. The study is being conducted in close collaboration with the American Society for Colposcopy and Cervical Pathology.

Following a standardized protocol for biopsy placement based on decreasing order of lesion severity as judged by colposcopic impression, up to four biopsies, including one randomly taken, were performed on 700 women referred to colposcopy. Endocervical curettage was performed in women age 30 and older. Colposcopic impression, acetowhitening, and biopsy placement was documented using the Boundary Marking Tool (BMT), a digital imaging system developed in collaboration with the National Library of Medicine. All biopsies taken from each woman were analyzed separately using conventional histology, HPV typing, and biomarkers.

Investigators quantified the incremental benefit of taking additional targeted and random biopsies, and found that a single targeted biopsy missed over a third of prevalent precancers. Very few precancers were found with random biopsies. The results of the study will impact colposcopy and cervical cancer screening procedures in general. Making colposcopy more effective is important in a time of extensive screening (smaller lesions are detected) and vaccination against HPV (leading to an overall reduction of high grade lesions).

Several secondary aims are addressed in the study, including evaluation of biomarkers for cervical precancers like p16/Ki-67 cytology and urinary HPV testing. Investigators are also studying the topographic distribution and functional relation of multiple lesions on the cervix using HPV genotyping and biomarkers for viral transformation.